1. Field of the Invention
This invention relates to an improvement in nucleic acid hybridization technology. Nucleic acids bind to complementary partners in a predictable manner such that the detection of complementary partners is possible. The acceleration of the binding process is desired objective and will find broad application in a variety of industrial, medical, and research uses. In particular this invention relates to the acceleration of nucleic acid hybridization by heterogeneous nuclear ribonucleoproteins [hnRNPs].
hnRNPs are naturally occurring proteins found in ribonuclear core particles which are approximately 20 nm in diameter and have a sedimentation coefficient of about 40S. The core particles are found in a variety of eucaryotes including fruit flies, rodents and man. The core particles are comprised of both ribonucleic acid and multiple core proteins. The precise purpose of the particles or of the role of hnRNPs are not presently understood. It is known that these particles are commonly associated with newly transcribed messenger RNA. It is presumed that they play a role in the splicing of the message.
2. Information Disclosure
The acceleration of annealing between complementary nucleic acids has been described. Christiansen C. and Baldwin, R.L., 1977, Catalysis of DNA Reassociation by the Escherichia coli DNA Binding Protein, J. Mol. Biol 115:441-454; Weinstock, G.M. et al., 1978, ATP-dependent renaturation of DNA catalyzed by the recA protein of Escherichia coli, Biochemistry 76:126-130; Cox, M.M. and Lehman, I.R., 1981, Renaturation of DNA: a novel reaction of histones, Nucleic Acid research 9:389-399; Keener S.L. and McEntree, K., 1984, Homologous pairing of single-stranded circular DNAs catalyzed by recA protein, Nucleic Acids Research 12:6127-6139; and Bryant, F.R. et al., 1989, Kinetic Modeling of the RecA Protein Promoted Renaturation of Complementary DNA Strands, Biochemistry 28:1062-1069.
Heterogeneous nuclear particles was known and reviewed by Dreyfuss, G., et al., Mar. 1988, Heterogeneous nuclear ribonucleoprotein particles and the pathway of mRNA formation, TIBS 13:86-90 and Bandziulis, R.J. et al., 1989, RNA-binding proteins as developmental regulators, Genes & Devel. 3:431-437.
The A1 core protein has been implicated in helix-destabilizing. Williams, K.R. et al., 1985, Amino acid sequence of the UPI calf thymus helix-destabilizing protein and its homology to an analogous protein from mouse myeloma, Proc. Natl. Acad. Sci. U.S.A. 82:5666-5670. The cDNA encoding A1 hnRNP from rat has been cloned and expressed. Cobianchi, F. et al., 1986, Structure of Rodent Helix-destabilizing Protein Revealed by cDNA Cloning, J of Biol. Chem. 261:3536-3543. The A1 hnRNP from human cells has been isolated and purified. Kumar, A. et al., 1986, Purification and Domain Structure of Core hnRNP Proteins A1 and A2 and Their Relationship to Single-stranded DNA-Binding Proteins, J. Biol. Chem. 261:11266-11273. Kumar et al also reported on the ability of A1 hnRNP to mediate duplex formation between synthetic polynucleotides.
The characterization of mammalian A1 hnRNP was described by Cobianchi, F. et al. 1988, Mammalian Heterogeneous Nuclear Ribonucleoprotein Complex Protein Al, J. Biol. Chem. 263:1063-1071 and by Merrill B.M. et al., 1988, Phenylalanines That Are Conserved among Several RNA-binding Proteins Form Part of A Nucleic Acid-binding Pocket in the A1 Heterogeneous Nuclear Ribonucleoprotein, J. Biol. Chem. 263:3307-3313.